This invention relates to vehicle suspensions and, more particularly, to a torsion bar type suspension with power trim height adjusting means.
It is known in the art to provide a vehicle suspension including torsion bars as the vehicle-supporting spring elements. In a typical embodiment, a torsion bar is connected with the lower control arm connecting an associated one of the vehicle wheels with the vehicle body. The torsion bar typically extends longitudinally, having an opposite end supported in a frame or body cross member. The cross member supported end is attached to a torsion lever which applies a predetermined torsion force for supporting the vehicle. An adjusting screw mounted in either the cross member or the lever engages the other for manually adjusting the lever to provide the desired torque setting of the torsion bar.
The present invention provides power adjustable means for remotely varying the torque applied to the torsion bars of a vehicle torsion bar suspension so that the trim height of the suspension may be remotely controlled by the vehicle operator. The height adjustment may be up or down from a normal running height. The suspension may be made capable of lowering vehicle height to allow entry into or passage through a low clearance location, such as a parking garage or overpass. Alternatively, the suspension could be capable of raising the vehicle height for passage over rough terrain. Various forms of adjusting mechanisms may be utilized including, for example, lever and wheel type torsion adjusting means with linear or rotary actuators.
For example, the torsion member may be a torsion lever similar to that of the manually adjusted prior art embodiment. A linear actuator is provided between the torsion lever and the vehicle cross member to adjust the torsion lever in response to an operator initiated signal. The linear actuator may be of any suitable type, such as a pneumatic or hydraulic cylinder or device, or an electric motor driven actuator, such as a powered screw or the like. The actuator is adjustable to at least two positions and rotates the torsion lever between these positions to establish either a high or low height position of the vehicle suspension in which the vehicle can be operated.
For some types of actuators, such as a hydraulic cylinder or bag, position locks may be required to fix the associated torsion levers in their adjusted positions so that the spring rates of the torsion bar suspension will not be changed by the effect of the pneumatic actuator applied as part of the system. To adjust the mechanism, the locks would first be released so that the actuators could move the torsion levers to another position after which the locks would again be applied, if required.
A feature of these embodiments of the invention is that they may be relatively easily applied to an existing torsion bar suspension system that does not have a remotely adjustable trim height feature. The modifications to the existing system would only affect a part of the vehicle to which the torsion bars are anchored and would involve packaging of the lever arm actuator and lock/latch mechanism, if required.
In other embodiments of the invention, the torsion member could be a wheel, such as a sprocket, gear or the like, driven by a power drive of any suitable type, One example is an electric motor driven worm drive connected to a chain drive sprocket. The drive sprocket is connected by chain connectors with driven adjuster sprockets on both of the torsion bars supporting one end of a vehicle. Remotely controlled operation of the worm drive actuates both driven sprockets to adjust both torsion bars simultaneously to vary the vehicle trim height at the associated vehicle end.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.